The present invention relates to a novel ErbB-4 ligand, referred to herein as Neuregulin-4 (NRG-4), to polynucleotide sequences encoding said NRG-4, to oligonucleotides and oligonucleotide analogs derived from said polynucleotide sequences, to a display library displaying short peptides derived from said NRG-4, to antibodies recognizing said NRG-4, to peptides or peptide analogs derived from said NRG-4, and to pharmaceutical compositions and methods of employing said peptides or peptide analogs, said oligonucleotides and oligonucleotide analogs, and/or said polynucleotide sequences to up-regulate or down-regulate ErbB-4 receptor activity.
Cell-to-cell signaling is an essential feature of multi-cellular organisms, playing important roles in both the unfolding of developmental diversification as well as mediating the homeostasis of vastly different cell types. A large number of tyrosine kinase growth factor receptors play key roles in this process. Type-1 tyrosine kinase receptors, also known as ErbB/HER proteins, comprise one of the better-characterized families of growth factor receptors, of which the epidermal growth factor receptor (ErbB-1) is the prototype [reviewed in (Burden and Yarden, 1997)]. The ErbB family constitutes four known receptors which dimerize upon ligand stimulation, transducing their signals by subsequent autophosphorylation catalyzed by an intrinsic cytoplasmic tyrosine kinase, and recruiting downstream signaling cascades.
The ErbB receptors are activated by a large number of ligands. Depending upon the activating ligand, most homodimeric and heterodimeric ErbB combinations can be stabilized upon ligand binding (Tzahar et al., 1996), thus allowing a complex, diverse downstream signaling network to arise from these four receptors. The choice of dimerization partners for the different ErbB receptors, however, is not arbitrary.
Spatial and temporal expression of the different ErbB receptors do not always overlap in vivo, thus narrowing the spectrum of possible receptor combinations that an expressed ligand can activate for a given cell type (Erickson et al., 1997; Gassmann et al., 1995; Lee et al., 1995; Pinkas-Kramarski et al., 1997; Riethmacher et al., 1997).
Furthermore, a hierarchical preference for signaling through different ErbB receptor complexes takes place in a ligand-dependent manner. Of these, ErbB-2-containing combinations are often the most potent, exerting prolonged signaling through a number of ligands, likely due to an ErbB-2-mediated deceleration of ligand dissociation (Karunagaran et al., 1996; Tzahar et al., 1996; Wang et al., 1998).
In contrast to possible homodimer formation of ErbB-1 and ErbB-4, for ErbB-2, which has no known direct ligand, and for ErbB-3, which lacks an intrinsic tyrosine kinase activity (Guy et al., 1994), homodimers either do not form or are inactive.
Heterodimeric ErbB complexes are arguably of importance in vivo. For example, mice defective in genes encoding either NRG-1, or the receptors ErbB-2 or ErbB-4, all result in identical failure of trabeculae formation in the embryonic heart, consistent with the notion that trabeculation requires activation of ErbB-2/ErbB-4 heterodimers by NRG-1 (Gassmann et al., 1995; Lee et al., 1995; Meyer and Birchmeier, 1995).
At the biochemical level, the known ErbB ligands fall into several categories (Riese et al., 1996b). One category, the ErbB-1 ligands, includes EGF, Transforming Growth Factor xcex1 (TGFxcex1), Epiregulin, Amphiregulin, Betacellulin and the Heparin-binding EGF (HB-EGF) (Higashiyama et al., 1991; Marquardt et al., 1984; Shing et al., 1993; Shoyab et al., 1989; Toyoda et al., 1995). To different extents, these ErbB-1 binding ligands can also activate other receptors of the ErbB family, and hence may mediate distinct signaling outputs for a given cell type [reviewed in (Tzahar and Yarden, 1998)].
Another category of ErbB ligands comprises the Neuregulin (NRG) family. NRG-1 [also named Neu differentiation factor (NDF), Heregulin, Glial Growth factor, and Acetylcholine Receptor Inducing Activity] was first identified by its ability to indirectly phosphorylate ErbB-2 (Holmes et al., 1992; Peles et al., 1992; Wen et al., 1992). Subsequently, NRG-1 was found to directly bind ErbB-3 and ErbB-4 and to sequester ErbB-2 by receptor dimerization (Peles et al., 1993; Plowman et al., 1993; Sliwkowski et al., 1994; Tzahar et al., 1994). Multiple isoforms of NRG-1 exist which amongst other roles, permit heterogeneous binding affinities to different ErbB complexes (Tzahar et al., 1994). The NRG family now includes also two isoforms of NRG-2 (Busfield et al., 1997; Carraway et al., 1997; Chang et al., 1997; Higashiyama et al., 1997), of which the alpha isoform is a pan-ErbB ligand (Pinkas-Kramarski et al., 1998), and NRG-3, a ligand of ErbB-4 (Zhang et al., 1997).
The multiplicity of genes encoding ErbB-1 ligands, contrasting with the small number of known genes encoding ligands for ErbB-3 or ErbB-4 (namely: NRGs), led the inventors of the present invention to believe in the existence of additional NRG genes in the genome of mammals.
A fourth Neuregulin, denoted NRG-4, which acts through the ErbB-4 receptor tyrosine kinase is reported herein. In addition to its novel structure, this growth factor displays a pattern of expression different from other EGF-like molecules.
Thus, the ErbB/HER family of receptor tyrosine kinases include four receptors that bind a large number of growth factor ligands sharing an epidermal growth factor (EGF)-like motif. Whereas ErbB-1 binds seven different ligands whose prototype is EGF, the three families of Neuregulins (NRGs) bind ErbB-3 and/or ErbB-4. While reducing the present invention to practice a fourth neuregulin, NRG-4, that acts through ErbB-4, has been identified, isolated and characterized. The predicted pre-NRG-4 is a transmembrane protein carrying a unique EGF-like motif and a short cytoplasmic domain. A synthetic peptide encompassing the full-length EGF-like domain induces growth of interleukin-dependent cells ectopically expressing ErbB-4, but not cells expressing the other three ErbB proteins or their combinations. Consistent with specificity to ErbB-4, NRG-4 can displace an ErbB-4-bound NRG-1 and can activate signaling downstream of this receptor. Expression of NRG-4 mRNA was detected in the adult pancreas and weakly in muscle. The primary structure and the pattern of expression of NRG-4, together with the strict specificity of this growth factor to ErbB-4, suggest a physiological role distinct to that of the known ErbB ligands. This strict specificity of binding can be exploited in numerous biopharmaceutical purposes.
According to one aspect of the present invention there is provided an isolated nucleic acid comprising a geonomic, complementary or composite polynucleotide sequence encoding a polypeptide being capable of binding to a mammalian ErbB-4 receptor and including a stretch of amino acids at least 95% homologous to a stretch of amino acids derived from SEQ ID NO:15 as determined using the BestFit software of the Wisconsin sequence analysis package, utilizing the Smith and Waterman algorithm, where gap creation penalty equals 8 and gap extension penalty equals 2.
According to another aspect the polynucleotide encodes a polypeptide which is at least 50% homologous to at least positions 4-50 of SEQ ID NOs:2 or 15 as determined using the BestFit software of the Wisconsin sequence analysis package, utilizing the Smith and Waterman algorithm, where gap creation penalty equals 8 and gap extension penalty equals 2.
According to preferred embodiments, the polynucleotide according to this aspect of the present invention encodes a polypeptide as set forth in SEQ ID NOs:2 or 15 or a portion thereof, preferably a portion which retains the binding activity.
According to still preferred embodiments, the polynucleotide according to this aspect of the present invention includes a polynucleotide stretch at least 80% identical to positions 55-190 of SEQ ID NO:14 as determined using the BestFit software of the Wisconsin sequence analysis package, utilizing the Smith and Waterman algorithm, where gap weight equals 50, length weight equals 3, average match equals 10 and average mismatch equals xe2x88x929.
Alternatively or additionally, the polynucleotide according to this aspect of the present invention is preferably hybridizable with SEQ ID NOs:1 or 14.
Hybridization for long nucleic acids (e.g., above 200 bp in length) is effected according to preferred embodiments of the present invention by stringent or moderate hybridization, wherein stringent hybridization is effected by a hybridization solution containing 10% dextrane sulfate, 1 M NaCl, 1% SDS and 5xc3x97106 cpm 32p labeled probe, at 65xc2x0 C., with a final wash solution of 0.2xc3x97SSC and 0.1% SDS and final wash at 65xc2x0 C.; whereas moderate hybridization is effected by a hybridization solution containing 10% dextrane sulfate, 1 M NaCl, 1% SDS and 5xc3x97106 cpm 32p labeled probe, at 65xc2x0 C., with a final wash solution of 1xc3x97SSC and 0.1% SDS and final wash at 50xc2x0 C.
Yet alternatively or additionally, the polynucleotide according to this aspect of the present invention is preferably at least 50% identical with SEQ ID NOs:1 or 14 as determined using the BestFit software of the Wisconsin sequence analysis package, utilizing the Smith and Waterman algorithm, where gap weight equals 50, length weight equals 3, average match equals 10 and average mismatch equals xe2x88x929.
According to preferred embodiments the polynucleotide according to this aspect of the present invention is as set forth in SEQ ID NOs:1 or 14 or a portion thereof, said portion preferably encodes a polypeptide retaining the binding activity.
According to another aspect of the present invention there is provided a nucleic acid construct comprising the isolated nucleic acid described herein. According to a preferred embodiment the nucleic acid construct according to this aspect of the present invention further comprising a promoter for regulating expression of the isolated nucleic acid in a sense of antisense orientation.
Alternatively, the nucleic acid construct according to this aspect of the present invention further comprising a positive and a negative selection markers and may therefore be employed for selecting homologous recombination events, including, but not limited to, homologous recombination employed in knock-in and knock-out procedures.
Consequently, according to yet another aspect of the present invention there is provided a host cell or animal comprising a nucleic acid construct as described herein.
According to still another aspect of the present invention there is provided an oligonucleotide of at least 17 bases specifically hybridizable with the isolated nucleic acid described herein.
Hybridization of shorter nucleic acids (below 200 bp in length, e.g. 17-40 bp in length) is effected by stringent, moderate or mild hybridization, wherein stringent hybridization is effected by a hybridization solution of 6xc3x97SSC and 1% SDS or 3 M TMACI, 0.01 M sodium phosphate (pH 6.8), 1 mM EDTA (pH 7.6), 0.5% SDS, 100 xcexcg/ml denatured salmon sperm DNA and 0.1% nonfat dried milk, hybridization temperature of 1-1.5xc2x0 C. below the Tm, final wash solution of 3 M TMACI, 0.01 M sodium phosphate (pH 6.8), 1 mM EDTA (pH 7.6), 0.5% SDS at 1-1.5xc2x0 C. below the Tm; moderate hybridization is effected by a hybridization solution of 6xc3x97SSC and 0.1% SDS or 3 M TMACI, 0.01 M sodium phosphate (pH 6.8), 1 mM EDTA (pH 7.6), 0.5% SDS, 100 xcexcg/ml denatured salmon sperm DNA and 0.1% nonfat dried milk, hybridization temperature of 2-2.5xc2x0 C. below the Tm, final wash solution of 3 M TMACI, 0.01 M sodium phosphate (pH 6.8), 1 mM EDTA (pH 7.6), 0.5% SDS at 1-1.5xc2x0 C. below the Tm, final wash solution of 6xc3x97SSC, and final wash at 22xc2x0 C.; whereas mild hybridization is effected by a hybridization solution of a hybridization solution of 6xc3x97SSC and 1% SDS or 3 M TMACI, 0.01 M sodium phosphate (pH 6.8), 1 mM EDTA (pH 7.6), 0.5% SDS, 100 xcexcg/ml denatured salmon sperm DNA and 0.1% nonfat dried milk, hybridization temperature of 37xc2x0 C., final wash solution of 6xc3x97SSC and final wash at 22xc2x0 C.
According to an additional aspect of the present invention there is provided a pair of oligonucleotides each of at least 17 bases specifically hybridizable with the isolated nucleic acid described herein in an opposite orientation so as to direct exponential amplification of a portion thereof in a nucleic acid amplification reaction.
According to yet an additional aspect of the present invention there is provided a nucleic acid amplification product obtained using the pair of primers described herein.
According to still an additional aspect of the present invention there is provided an antisense oligonucleotide comprising a polynucleotide or a polynucleotide analog of at least 10 bases being hybridizable in vivo, under physiological conditions, with a portion of a polynucleotide strand encoding a polypeptide at least 50% homologous to at least positions 4-50 of SEQ ID NOs:2 or 15 as determined using the BestFit software of the Wisconsin sequence analysis package, utilizing the Smith and Waterman algorithm, where gap creation penalty equals 8 and gap extension penalty equals 2.
According to a further aspect of the present invention there is provided a pharmaceutical composition comprising the antisense oligonucleotide described herein and a pharmaceutically acceptable carrier.
According to still a further aspect of the present invention there is provided a ribozyme comprising the antisense oligonucleotide described herein and a ribozyme sequence fused thereto.
According to yet a further aspect of the present invention there is provided a recombinant or synthetic protein comprising a polypeptide being capable of binding to a mammalian ErbB-4 receptor and including a stretch of amino acids at least 95% homologous to a stretch of amino acids derived from SEQ ID NO:15 as determined using the BestFit software of the Wisconsin sequence analysis package, utilizing the Smith and Waterman algorithm, where gap creation penalty equals 8 and gap extension penalty equals 2. Most preferably the polypeptide includes at least a portion of SEQ ID NOs:2 or 15. Additionally or alternatively, the polypeptide according to this aspect of the present invention is preferably encoded by a polynucleotide hybridizable with SEQ ID NOs:1 or 14 or a portion thereof under any of the stringent or moderate hybridization conditions described above for long nucleic acids. Still additionally or alternatively, the polypeptide according to this aspect of the present invention is preferably encoded by a polynucleotide at least 50% identical with SEQ ID NOs:1 or 14 or portions thereof as determined using the BestFit software of the Wisconsin sequence analysis package, utilizing the Smith and Waterman algorithm, where gap weight equals 50, length weight equals 3, average match equals 10 and average mismatch equals xe2x88x929.
According to still a further aspect of the present invention there is provided a pharmaceutical composition comprising, as an active ingredient, the recombinant protein described herein and a pharmaceutical acceptable carrier.
According to another aspect of the present invention there is provided a peptide or a peptide analog comprising a stretch of at least 6 consecutive amino acids or analogs thereof derived from a polypeptide at least 50% homologous to at least positions 4-50 of SEQ ID NOs:2 or 15 as determined using the BestFit software of the Wisconsin sequence analysis package, utilizing the Smith and Waterman algorithm, where gap creation penalty equals 8 and gap extension penalty equals 2. Preferably, the peptide or a peptide analog according to this aspect of the present invention comprises a stretch of at least 6 consecutive amino acids or analogs thereof derived from SEQ ID NOs:2 or 15.
According to still another aspect of the present invention there is provided a display library comprising a plurality of display vehicles (such as phages, viruses or bacteria) each displaying at least 6 consecutive amino acids derived from a polypeptide at least 50% homologous to at least positions 4-50 of SEQ ID NOs:2 or 15 as determined using the BestFit software of the Wisconsin sequence analysis package, utilizing the Smith and Waterman algorithm, where gap creating penalty equals 8 and gap extension penalty equals 2. According to a preferred embodiment of this aspect of the present invention substantially every 6 consecutive amino acids derived from the polypeptide are displayed by at least one of the plurality of display vehicles, so as to provide a highly representative library. Preferably, the consecutive amino acids or amino acid analogs of the peptide or peptide analog according to this aspect of the present invention are derived from SEQ ID NOs:2 or 15.
According to still another aspect of the present invention there is provided an antibody comprising an immunoglobulin specifically recognizing a polypeptide at least 50% homologous to at least positions 4-50 of SEQ ID NOs:2 or 15 as determined using the BestFit software of the Wisconsin sequence analysis package, utilizing the Smith and Waterman algorithm, where gap creation penalty equals 8 and gap extension penalty equals 2. According to a preferred embodiment of this aspect of the present invention the antibody specifically recognizing the polypeptides set forth in SEQ ID NOs:2 or 15. The antibody according to this aspect of the present invention can be, for example, a polyclonal antibody, a monoclonal antibody, a humanized antibody, a single chain antibody or an immunoreactive derivative (e.g., portion) of an antibody.
According to yet another aspect of the present invention there is provided a pharmaceutical composition comprising, as an active ingredient, an agent for regulating an endogenous protein affecting ErbB-4 activity, the endogenous protein being at least 50% homologous to at least positions 4-50 of SEQ ID NOs:1 or 15 as determined using the BestFit software of the Wisconsin sequence analysis package, utilizing the Smith and Waterman algorithm, where gap creation penalty equals 8 and gap extension penalty equals 2.
According to yet another aspect of the present invention there is provided a method of regulating an endogenous protein activity affecting ErbB-4 activity the method comprising the steps of administering an agent for regulating the endogenous protein activity, the endogenous protein being at least 50% homologous to at least positions 4-50 of SEQ ID NOs:1 or 15 as determined using the BestFit software of the Wisconsin sequence analysis package, utilizing the Smith and Waterman algorithm, where gap creation penalty equals 8 and gap extension penalty equals 2.
According to still further features in the described preferred embodiments the agent serves for altering, e.g., upregulating, the activity.
According to still further features in the described preferred embodiments the agent includes an expressible sense polynucleotide at least 50% identical with SEQ ID NOs:1 or 14 as determined using the BestFit software of the Wisconsin sequence analysis package, utilizing the Smith and Waterman algorithm, where gap weight equals 50, length weight equals 3, average match equals 10 and average mismatch equals xe2x88x929.
According to still further features in the described preferred embodiments the agent includes a polypeptide at least 50% homologous to at least positions 4-50 of SEQ ID NOs:2 or 15 as determined using the BestFit software of the Wisconsin sequence analysis package, utilizing the Smith and Waterman algorithm, where gap creation penalty equals 8 and gap extension penalty equals 2.
According to still further features in the described preferred embodiments the agent serves for downregulating the activity.
According to still further features in the described preferred embodiments the agent includes an expressible antisense polynucleotide at least 50% identical with SEQ ID NOs:1 or 14 as determined using the BestFit software of the Wisconsin sequence analysis package, utilizing the Smith and Waterman algorithm, where gap weight equals 50, length weight equals 3, average match equals 10 and average mismatch equals xe2x88x929.
According to still further features in the described preferred embodiments the agent includes an antisense oligonucleotide which includes a polynucleotide or a polynucleotide analog of at least 10 bases which is hybridizable in vivo, under physiological conditions, with a portion of a polynucleotide strand encoding a polypeptide at least 50% homologous to at least positions 4-50 of SEQ ID NOs:2 or 15 as determined using the BestFit software of the Wisconsin sequence analysis package, utilizing the Smith and Waterman algorithm, where gap creation penalty equals 8 and gap extension penalty equals 2.
According to still further features in the described preferred embodiments the agent includes a peptide or a peptide analog representing a stretch of at least 6 consecutive amino acids or analogs thereof derived from a polypeptide at least 50% homologous to at least positions 4-50 of SEQ ID NOs:2 or 15 as determined using the BestFit software of the Wisconsin sequence analysis package, utilizing the Smith and Waterman algorithm, where gap creation penalty equals 8 and gap extension penalty equals 2.
The present invention successfully addresses the shortcomings of the presently known configurations by disclosing a novel Neuregulin which specifically binds ErbB-4 with somewhat lower affinity as is compared to, for example, NRG-1xcex2. Additional advantages, novel features and utilities of the various aspects of the present invention are described in the following sections of this application.